Sustainable Mining and Metallurgy

Abstract:A large photovoltaic power station using intelligent solar tracking control system enjoys stable operation for years. This article introduced the composition of the sun tracking system, summarized and analyzed its mechanical characteristics, control logic, control mode and other aspects. It is believed that the stable operation of the tracking control system benefits from advanced management concepts, complete hardware systems and safe control logic. Finally, the advantages of tracking photovoltaic power station were analyzed by comparing the power generation of tracking photovoltaic power station and fixed photovoltaic power station. The analysis shows that the intelligent tracking control system adopts the timing interval control mode, and the tracking error is less than 3%; tracking does not depend on external sensors and is not subject to external disturbances; the structure is simple and stable; it doesn’t start motor frequently, reducing the impact of a large number of motor start and stop on the grid.

Abstract:China’s energy consumption and production scale are among the highest in the world, where carbon emissions from coal-firing power plants remain high, coal prices are rising, power shortages occur frequently, and new energy development is constrained. Under the guidance of the “2-stage carbon reduction” goal, it is urgent to explore high-quality energy development paths. In the process of building a clean, low-carbon and secure energy system, on the basis of steadily achieving “coal reduction”, it is necessary to increase support for new energy, increase the proportion of non-fossil energy, and improve the storage and regulation capabilities of the energy system, gradually achieve the adjustment of the energy structure and build a new power system with new energy as the mainstay.

Abstract:During the production process of a zinc cell house, a large amount of acid mist and water vapor are generated, and the environment in the plant building is harsh. This article introduced limitations of the natural ventilation technology and mechanical ventilation-top cooling tower exhaust ventilation technology currently used in zinc cell houses.Based on the motion characteristics of acid mist，the principles, advantages and disadvantages of the various ventilation schemes such as mechanical ventilation-vortex ventilation, mechanical ventilation-down exhaust ventilation were emphatically compared with examples. According to the actual situation, suggestions for the selection of ventilation schemes were given, and new ideas for improving the workshop environment were put forward.

Abstract:Feed concentration is one of the critical indicators for the nickel laterite pressure acid leaching process. This paper systematically studied and analyzed the influence of feed concentration in one Nickel-cobalt Project on slurry fluidity, water consumption, steam consumption, nickel and cobalt output, and the life of the check valve of the autoclave. The studies show that the increase in feed concentration can not only save water consumption, but also reduce steam consumption, raise output, extend the service life of the check valve of the feed pump of the autoclave, increase the operational availability of the equipment, and reduce the unit production cost, while it will accelerate the yield stress increase and reduce the slurry fluidity. Therefore, the slurry underflow concentration should be increased as much as possible under the conditions allowed by the slurry fluidity and the equipment performance.

Abstract:Targeted at the poor and unstable quality of the cooling water for aluminum alloy slab casting of one enterprise, the reasons for this problem were analyzed from such aspects as the operation mode of the cooling water system, slab casting process, production method, and makeup water quality. By improving the equipment operation mode, stabilizing the production capacity and casting process, regularly sampling, analyzing and testing the water quality, and exploring the water replenishment law, the cooling water quality was significantly improved, met the requirements of casting process, and effectively improved the quality of flat ingots.

Abstract:Rolling aluminum has many adverse effects on production including reducing the stability of the electrolytic cell, causing current drain which affects energy consumption indicators, and even cell shutdowns and blackouts in severe cases. This article introduced in detail the performance of aluminum electrolytic cells when aluminum rolling occurs, as well as the root causes and precursory characteristics of aluminum rolling. A specific analysis was carried out on the five common reasons that may cause aluminum rolling during the electrolytic production process, preventive measures targeted at each cases were put forward accordingly and recommendations for handling aluminum rolling were finally given to provide reference to prevent aluminum rolling and handle the cell with aluminum rolling occurrence during aluminum electrolysis.

Abstract:Incineration residues such as MSW incineration fly ash, fly ash and bottom ash from hazardous waste incinerators are hazardous wastes defined, and melting and vitrification process is the best way to treat incineration residues, realizing hazardous waste harmless treatment, minimizing and recycling. This paper introduced the current situation of production and disposal technology of incineration residues in China, the mechanism of glass erosion and the influence of glass composition system on the chemical stability of glass. This paper also reviewed the development of hazardous waste melting technology, and introduced the principles and application cases of electrothermal type and fuel type melting technology. Combined with the composition characteristics and regional output differences of incineration residues in China, resistance melting process and side-submerged combustion smelting process were suggested to be adopted.

Abstract:To understand the status of soil pollution in acid dumps of polymetallic mines, a study was carried out for some historical acid mine dump, collecting 9 mixed soil samples and analyzing heavy metal contents of Pb, Cu, Zn and Cd in the soil. The present situation and spatial distribution characteristics of heavy metal pollution were discussed by using single factor index method, Nemerow index method and ArcGIS spatial interpolation method, and the soil environment in the study area was evaluated. The results show as follows: 1) The average pH value of soil in the study area is 3.70, which is highly acidic. There is heavy metal pollution in the study area, and the contents of Pb, Cu, Zn and Cd are all higher than the risk filter value, with the average contents of 6134.36mg/kg, 642.01mg/kg, 1035.83mg/kg and 1.52mg/kg, and are 87.6 times, 12.8 times, 5.2 times, and 5.1 times of the risk filter value, respectively; 2) The soil environmental quality assessment grade in the study area is V, indicating heavy pollution. The average pollution index Pi value of the four metal elements is ranked as: P_Pb(87.63)＞P_Cu(12.84)＞P_Zn(5.18)＞P_Cd(5.08). The contaminated areas of Pb and Zn are larger, the average Pcom value is 65.06, and the difference among sample points is large, ranging from 28.23 to 89.23; 3) The pH value and the heavy metal element Cu of soil in the study area show significant positive correlation, and the correlation among heavy metal elements is weak.

Abstract:This paper analyzed the off-gas generation situation of domestic waste incineration, compared the local emission standards, national standards and international standards of waste incineration off-gas. Combined with the application of desulfurization technology in domestic projects, this paper also analyzed and compared the principles, influencing factors, equipment, advantages and disadvantages of semi-dry desulfurization, dry desulfurization and wet desulfurization technologies, as well as the problems existing in projects. According to different off-gas characteristics and environmental protection emission requirements, semi-dry, dry and wet desulfurization processes can be combined to achieve better results, however, how to choose the appropriate desulfurization technology to lower the investment and operation cost is still being explored.

Abstract:The mining technology of southern ionic rare earth ore has experienced the evolution of pool leaching and heap leaching, and the in-situ leaching technology is currently used. In-situ leaching mining technology has the advantages of not damaging surface plants and producing tailings, but there are still risks such as landslides, pollution of surface water and shallow groundwater. Based on the analysis of in-situ leaching mechanism and process flow, the key points of pollution prevention and environmental protection management in the design stage, construction stage, production stage and later production stage of ionic rare earth mining were introduced. Practice has proved that by taking reasonable pollution prevention and control measures, the disturbance of the mining of ionic rare earth mines on the surface water, groundwater, soil and other ecological environment in the mining area and surrounding areas is controllable, and the green development of ionic rare earth mines is realized.

Abstract:The authors herein elaborated on the application research and trend of development on sewage sludge treatment technologies such as concentration, dewatering, digestion, pyrolysis and drying, as well as sludge disposal technologies such as sanitary landfill, use on land, reuse as building materials and incineration, focusing on the analysis of advantages and disadvantages of the main types of incinerators (fluidized bed, multi-hearth incinerator, rotary kiln, etc.) in order to provide reference for the selection of incinerators for sludge disposal.

Abstract:With the increasing amount of waste from fiber-reinforced thermoset composites, their recycling has become another common concern of the industry, which requires urgent solution. The author herein introduced and compared the main technologies and methods for recycling fiber-reinforced thermoset composites at home and abroad, including physical recovery method, energy recovery method and chemical recovery method, analyzed with application cases the status quo of relevant technological research and industrialization at home and abroad, and proposed suggestions based on the industry’s development trend.

Abstract:Due to the backward mining technology and management concept, disorderly exploitation of the building stone mine results in severe damage to the topography and landform and a great number of high and steep slopes with thin soil cover and poor site condition for plant growth. To address this, the wire mesh and soil spraying seeding technology is widely applied in the field of rock slope ecological restoration. This paper summarized this technology’s applicable conditions, process flow, technical essentials and equipment for each link. This technology improves soil adhesion by applying wire mesh to the slope, and allows manual control of substrate’s soil fertility so as to create favorable site conditions for vegetation and serve as an effective means of rock slope ecological restoration.

Abstract:This paper introduced the comprehensive utilization technology of SiCl4, a byproduct from polysilicon production by Siemens process, and its status quo. Specifically, this paper elaborated on how SiCl4 is used to produce fumed silica, ethyl silicate, optical fiber and trichlorosilane from aspects of principles, strengths and shortcomings, issues and improvement, focused on the latest progress in SiCl4 hydrogenation technology, and put forth suggestions and solutions to difficulties in hydrogenation, pointing out the direction and providing guidance for polysilicon technology development in China.

Abstract:This paper gave a brief introduction to strengths and shortcomings of thermal relay, electronic motor protector and intelligent motor protector, elaborated on proper selection of intelligent motor protector, compared several common operating modes of intelligent motor protector, including protected mode, terminal control mode, half-duplex communication mode and full-duplex communication mode, introduced the actual situation of the application of these four modes, and finally put forward suggestions and solutions to issues related to intelligent motor protector’s industrial application.

Abstract:This paper briefly introduced the era background of promoting digital transformation in non-ferrous metal industry, and put forward the implementation path of promoting digital transformation in non-ferrous metal industry based on the characteristics and current situation of non-ferrous metal industry. To achieve digital transformation, we must adhere to strategic guidance, overall planning, step-by-step implementation. We should strengthen the top-level design, formulate strategic planning for digital transformation and development; improve digital governance capabilities and improve basic platform construction; with innovation as the core driving force, build green intelligent mines and environmental protection intelligent factories; strengthen basic application research and build an industrial chain ecosystem with resource sharing, high coordination and integrated development; cultivate digital talents, build a digital transformation team, and build a digital transformation organizational structure.

Abstract:Taking a project as an example, this paper introduced the application and practice of safety production standardization, and demonstrated the necessity of safety production standardization. In view of the current situation of safety production in the construction industry, this paper sort out the problems existing in the application of standardized management of safety production at the present stage, such as the low level of standardized management, the insufficient investment in standardized management, and the lack of appropriate information tools in standardized management, and put forward the countermeasures such as strengthening responsibility assessment, carrying out management standardization, implementing financial guarantee and innovating information tools, etc.

Abstract:Starting from the concept of general contracting EPC of construction project, this paper discussed its development history, introduced its subjective and objective necessity and advantages, and emphatically expounded the connotation of cost determination and control of EPC project. In addition, this paper also introduced in detail the basis of cost determination and the problems that need to be paid attention to, and expounded the key points of cost control from the aspects of equipment and material procurement costs, construction and installation engineering costs, and management costs. In the process of EPC project execution, design is the foundation and should be paid more attention to. Cost control is the key, especially the prior cost control.